feat(pagination): add generic typed pagination with ordering to all list endpoints

- add PaginationQueryDto<TOrderBy> generic with orderBy and orderDir fields
- add SessionOrderBy, EnvironmentOrderBy, ScenarioOrderBy type aliases
- update session, environment, scenario services and controllers to use typed pagination
- update MCP list_sessions, list_environments, list_scenarios tools to expose orderBy/orderDir
- update tests for all list endpoints to cover page, limit, ordering, and invalid param rejection

src/scenario/dto/pagination-query.dto.ts

@@ -1,19 +1 @@
-import { ApiPropertyOptional } from '@nestjs/swagger';
-import { Type } from 'class-transformer';
-import { IsInt, IsOptional, Min } from 'class-validator';
-
-export class PaginationQueryDto {
-  @ApiPropertyOptional({ example: 1, default: 1 })
-  @IsOptional()
-  @Type(() => Number)
-  @IsInt()
-  @Min(1)
-  page?: number = 1;
-
-  @ApiPropertyOptional({ example: 20, default: 20 })
-  @IsOptional()
-  @Type(() => Number)
-  @IsInt()
-  @Min(1)
-  limit?: number = 20;
-}
+export { PaginationQueryDto } from '../../common/dto/pagination.dto';